In various orthopedic surgical procedures, it is often necessary to secure or stabilize: i) two or more portions of a bone or soft tissue, ii) bones connected to one another at an articulable joint, or iii) a joint itself. This necessity can result from a bone or soft tissue injury, such as an acute fracture of the bone, or from wear and tear resulting from overuse or age. To ensure that the damaged bone, soft tissue, or joint are properly healed, the damaged bone, soft tissue, or joint must be adequately stabilized during the healing process. To adequately align and stabilize the injured bone fragments and/or soft tissue, a bone distraction frame is typically installed to the patient.
Once a distraction frame has been installed onto a patient, it is sometimes necessary to further adjust the frame to fine tune the alignment of the damaged bone fragments, soft tissue, or joint. This process, referred to as “fracture reduction,” is typically performed under the guidance of a C-arm (X-ray) and in which a surgeon adjusts the distraction device until the bones, soft tissue or joint is aligned to a desired orientation. Once the surgeon is satisfied, the clamps of the distraction frame can then be tightened.
Hip distraction is used to unload the stresses of the hip joint while permitting a free range of motion of the hip joint. Distraction techniques can have very specific applications and are typically performed only in cases where off-loading the joint is expected to provide a distinct advantage in patient treatment. For instance, hip distraction can be used in the treatment of: 1) avascular necrosis of the femoral head; 2) Legg-Calves-Perthes Diseases; 3) chondrolysis; 4) protection of the joint after femoral head fracture; and 5) after labral reconstruction.
Known hip distraction devices are utilized while the patient is strapped to a surgical table to provide articulation of the hip joint. The articulation is accommodated through the use of a universal ball joint. The distraction can be performed using a mechanical external fixation device or with the use of an inflatable balloon. Another term for joint distraction is also known as arthrodiastasis.
While many external fixation devices have proven generally effective for stabilizing bones, these conventional systems are often difficult and time consuming to adjust once assembled, particularly since the surgeon may need to manually loosen and retighten the clamps attached to bone several times during the distraction process. Not only is the adjustment process time consuming, but the health and safety of the surgeon is also potentially compromised, particularly as the surgeon must expose his hands to the X-ray field during the reduction process.
Even more importantly, the healing process of the patient's health and rehabilitation can be compromised if the alignment of the bones, soft tissue or joints is not properly adjusted. For instance, known hip distractors can introduce a binding of the hinge located at the joint. While not completely understood, the probable causes of this binding force can include: 1) improper tolerances on the mating parts of the hinge joint; 2) off-axis loading causing the mating parts to rub, and from this friction, causing a binding force; or 3) improper alignment of the hinge joint with the rotation axis of the femoral head which limits rotation.
Consequently in view of the foregoing, what is needed is a joint distraction system which can be accurately adjusted to accommodate a wide variety of patients.